Ocean_Ography_Study_Sheet

*e r 6371km, oc d avg. 4k..mx 11k, oc covers 70% of e, lithosphere d 100km *crust-silicate, mantle-denser silicate, core-mostly iron*lithosphere 100km strong crust and mantle, Aesthenosphere weak partly melted mantle*oc-crust(lithosphere)-thinner 7km, denser, basaltic. cont- crust(lithosphere) – 20-70km, granitic*S-waves no water*Isostasy: litho floates on Aestho***Corral F-B-A*CaCo3*water bad/no light-plants leave corral-no rock*Cont. shelf s0.1-0.5 d100-130m w~70km, shelf break, Cont. slope s 4-10, ex 130m d 2000m + w-35, sediment fills-Cont. rise w 200-300km (see Submarine cyn)* Sudmarine cyn – gullies/canyons, cut by river/Turbidity crnts(dense mud/water mixture avalanche downslope) – sediment spreads & stops at end forming Deep sea fan ( as the abyssal fans next to each other combine, they form the continental rise*Abyssal plains –flat oc sediment covers its*guyots- flat top used to b area where breaking waves passed over*SOCAL boarder filled w/ shallow banks(or islands) & deep basins, formed by movements by diffrnt pieces of crust & related volcanic activity(not normal)seismically active still*Divergent (Rifting of continents= it is stretched until it breaks. basalt from the mantle will fill-in between the diverging cont. fragments. If divergent continues, a widening ocean basin is made (water fills in ex..pangea, baja CA, red sea) between cont. pieces, the youngest occurs in the middle of the oc ridge forming a mid-ocean ridge) makes ocean ridge system (balsaltic magma rises into the axial rift valley & is added to each plate, the ridge is younger and less dense so it stands up higher as it ages, cools & becomes denser it slides down sides (divergent makes ocean plate/basin/litho)..Divergent volcanoes are basalt and form oc litho. Convergent –subduction of denser plate, makes oc trench/volcanic arcs ... Andesite (cont. lithosphere) volcanic activity occurs( cont. lithosphere is made by convergent) (oc plate vs cont. plate – oc plate subducted..Cont vs Cont – Neither is dense enough) OC basin/Plate destroyed by convection, (divergent makes ocean plate/basin/litho) ..as the plate is subducted it gathers andesite and takes it down,( on the downslope of the subduction Wadati-benioff zone of earthquakes occur) when the andesite gets hot enough it melts and comes back up - Convergent volcanoes are andesite and form cont. litho.– Transform oc ridge makes plate and plates travel in the direction they were made, they rub against each other (fracture zones separate them), the older colder parts are lower, forming cliffs at fracture zones) as they pass. makes transform faults (ex.. San Andres) related to fracture zones ..*Earths Magnetism imprints are frozen into the lava as it cools based on the magnetic polarity of the time. Creating stripes(every 7-1.6m yrs) Strong strips=normal polarity N-S, weak strips=reversed polarity S-N - - (magnetic imprints tell us the earths age (4.5b) and the latitude volcanic rock mass was og created/located* Plate boundaries = oc ridge system, oc trench/volcanic rock, transform faults (related to fracture zones)*OC floor subsides as it gets older, cooler, denser* Hydro Thermal Circulation (hot springs)– cold water sinks, becomes warm and rises out of Hydrothermal Vents…as vent water cools, dissolves chemicals clump together, forming metal sulfite minerals, Sulfide in the vent water provides energy for food making known as Chemosynthesis (a process performed by Arches “bacteria”), which allows large amounts of life to exists by the vents. Black smokers= the hottest vents, thick with dissolved chemical (found in the middle of the oc ridges where it’s the hottest and youngest. Mantle Plume- s an upwelling of abnormally hot rock within the Earth's mantle. As plates slide across the plume, a trail of volcanoes will form (ex..Hawaii) plumes can also pop up on cont. plates (ex..Yosemite). * Convection = is movement up or down caused by density differences. (ex.. Hydro thermal circulation (hot springs), Mantle Plume, Subduction* Mantle Convection – a rising mantle plume may produce a “bulge” (or swelling) on earths surface. As the litho sphere bulges upward it may crack a plate to break. A plate fragment may slide down-hill off the bulge. Ex..Saudi Arabia ‘red sea & africa’. Another ex. Of mantle convection is subduction, plates w/ oldest edge are subducted rapidly at a shallow/steep angle.* Change in rate of plate motion (Sea level rises) 1. increased rate of plate motion (faster) 2. younger ocean lithosphere (on Avg) – younger =warmer=less dense ocean litho, less dense oc litho stands higher on the mantle (ocean basins are shallower) (Sea level lowers) 1. decreased rate of plate motion. 2. older oc litho= colder = denser. Denser oc litho sphere stands lower on the mantle (ocean basin is deeper) Himalayas=cont vs cont convergent, gulf CA=Divergent, red sea=divergent (mantle convection). Photo synthesis – solar energy, plant, organic matter ..VS ..Chemosynthesis – Chemicals, bacteria, organic matter